Modeling and Investigation of Self-Excited Reluctance Generators for Wind Applications

ln the last few years, wind energy conversion systems have been increasingly installed worldwide. The self. excited reluctance generators (SERGs) are found to be potential candidates as isolated wind turbine generators, especially for low- and medium-power applications. This paper focuses on the characteristics of SERG for wind turbine generation system. A simplifted dynamic model of the generation system with resistive load is built, discretized by backward Euler formula and simulated. With this model, the process of self-excitation, the effect of rotor acceleration and voltage variation with speed are investigated. After that, the active and reactive power (PQ) balances under steady state condition are proposed to determine the operating point of SERG system. Voltage regulation is achieved by variable capacitances, with the values obtained from PQ balances. Combining the power speed characteristics of wind turbine and SERG, the PQ balance is also used to determine the optimal excitation capacitor and load resistor to achieve the highest usage of wind power. This paper exhibits the performance of SERG for wind applications, and most importantly, makes the prediction of optimal capacitor and resistor for the highest energy conversion efficiency.